JP2009092208A - Control device for continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a transmission improved in control accuracy of a change gear ratio at a neutral position, while eliminating or dispensing with a sensor for detecting rotation of a drive pulley of a continuously variable transmission. <P>SOLUTION: When it is determined that a forward clutch is set at a neutral position for releasing the forward clutch (S10), a deviation between engine speed NE and turbine speed NT is computed (S14), and a feedback gain is set based on the computed deviation (S16), thrusts of a drive pulley and a driven pulley are computed based on the set feedback gain (S18), and oil pressures to be supplied to the drive pulley and the driven pulley are computed based on the computed thrusts (S20). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a continuously variable transmission, and more specifically, to improve the control accuracy of a gear ratio at a neutral position while removing or eliminating the use of a sensor that detects the rotation of a drive pulley of the continuously variable transmission. It relates to the device.

As a prior art of a device that performs speed change control by the rotational speed of the turbine and the driven pulley while removing the sensor that determines the rotation of the drive pulley of the continuously variable transmission, a technique described in Patent Document 1 can be cited. In the technique described in Patent Document 1, when the travel position (range) is selected and the input clutch is engaged, the rotational speed of the drive pulley matches the turbine rotational speed, and therefore the speed ratio is feedback controlled. At the same time, the gear ratio is feedforward controlled at the neutral position where the input clutch is released.
JP 2005-172010 A

  That is, in the technique described in Patent Document 1, the target rotational speed of the drive pulley is calculated based on the vehicle speed at the neutral position where the input clutch is released, and the calculated target rotational speed and the rotational speed of the driven pulley are A target gear ratio is calculated, then a target drive pulley pressure feedforward value is calculated based on the calculated target gear ratio, and the energization of the hydraulic pressure adjustment valve (electromagnetic valve) is adjusted to be the calculated value. The

  As described above, in the technique described in Patent Document 1, since the feed-forward control is performed at the neutral position where the input clutch is released, if the deviation between the target value and the actual value increases, There is a risk of starting performance deficiency due to the return delay.

  Accordingly, the object of the present invention is to solve the above-mentioned inconveniences, and to improve the control accuracy of the gear ratio at the neutral position while removing or eliminating the need to use the sensor for detecting the rotation of the drive pulley of the continuously variable transmission. It is to provide a control device for a continuously variable transmission.

  In order to achieve the above object, according to claim 1, a belt type continuously variable transmission which is connected to an internal combustion engine mounted on a vehicle via a torque converter and a clutch, and which has a drive pulley and a driven pulley. An engine speed sensor for detecting the speed of the internal combustion engine, a turbine speed sensor for detecting the turbine speed of the torque converter, an oil chamber and a hydraulic pressure of each of the drive pulley and the driven pulley. A hydraulic pressure adjusting valve that is inserted in an oil passage between the supply source and adjusts the oil pressure of the oil passage, and the throttle opening is determined to be in a fully closed position and a neutral position in which the clutch is released. The hydraulic pressure supplied to the drive pulley and the driven pulley so that the turbine speed matches the engine speed. It was composed as and a feedback control means for feedback controlling via the hydraulic control valve.

  In the control device for a continuously variable transmission according to claim 1, when it is determined that the throttle opening is in the fully closed position and the neutral position in which the clutch is released, the turbine speed matches the engine speed. As described above, since the hydraulic pressure supplied to the drive pulley and the driven pulley is feedback-controlled via the hydraulic pressure adjusting valve, the control accuracy of the transmission ratio can be improved.

  To explain this, when the inventor is in the neutral position, the clutch is released, but the turbine speed tends to be dragged by the hydraulic oil to the engine speed and the drive pulley speed. The present invention was made based on the knowledge that when the rotation speeds coincide, the rotation speed of the drive pulley also coincides with them.

  In other words, the idle rotation speed at the neutral position is constant, but the hydraulic pressure supplied to the drive pulley and the driven pulley is feedback controlled so that the rotation speed of the drive pulley matches the idle rotation speed regardless of the vehicle speed. did.

  In this way, by assuming that the drive pulley rotational speed is constant regardless of the vehicle speed, the locus when the gear ratio (drive pulley rotational speed / driven pulley rotational speed) returns to the low side as the vehicle speed decreases becomes the same. Therefore, the control accuracy of the gear ratio can be improved.

  The best mode for carrying out a continuously variable transmission control apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the overall control device of a continuously variable transmission according to an embodiment of the present invention.

  In FIG. 1, reference numeral 10 indicates an internal combustion engine (hereinafter referred to as “engine”). The engine 10 is mounted on a vehicle (partially indicated by drive wheels W).

  A throttle valve (not shown) arranged in the intake system of the engine 10 is mechanically disconnected from an accelerator pedal (not shown) arranged in the vehicle driver's seat, and is a DBW (actuator) such as an electric motor. Drive By Wire) mechanism 16 is connected and driven.

  The intake air metered by the throttle valve flows through an intake manifold (not shown) and mixes with fuel injected from an injector (fuel injection valve) 20 near the intake port of each cylinder to form an air-fuel mixture, When an intake valve (not shown) is opened, it flows into a combustion chamber (not shown) of the cylinder. In the combustion chamber, the air-fuel mixture is ignited and combusted, and after driving a piston (not shown) to rotate the crankshaft 22, exhaust gas is discharged outside the engine 10.

  The rotation of the crankshaft 22 of the engine 10 is input to the transmission 26 via the torque converter 24. That is, the crankshaft 22 is connected to the pump / impeller 24a of the torque converter 24, while the turbine runner 24b disposed opposite thereto and receiving fluid (hydraulic fluid) is connected to the main shaft (mission input shaft) MS. .

  The transmission 26 includes a continuously variable transmission (hereinafter referred to as “CVT”), and includes a drive pulley 26a disposed on the main shaft MS and a driven pulley 26b disposed on a counter shaft CS parallel to the main shaft MS. And a metal belt 26c hung between them.

  The drive pulley 26a includes a fixed pulley half 26a1 disposed on the main shaft MS and a movable pulley half 26a2 that can move relative to the fixed pulley half 26a1 in the axial direction. The driven pulley 26b includes a fixed pulley half 26b1 fixed to the countershaft CS and a movable pulley half 26b2 that can move relative to the fixed pulley half 26b1 in the axial direction.

  The CVT 26 is connected to the forward / reverse switching device 30. The forward / reverse switching device 30 includes a forward clutch 30a, a reverse brake 30b, and a planetary gear mechanism 30c disposed therebetween.

  In the planetary gear mechanism 30c, the sun gear 30c1 is fixed to the main shaft MS, and the ring gear 30c2 is fixed to the fixed pulley half 26a1 of the drive pulley 26a via the forward clutch 30a.

  A pinion 30c3 is disposed between the sun gear 30c1 and the ring gear 30c2. Pinion 30c3 is coupled to sun gear 30c1 by carrier 30c4. The carrier 30c4 is fixed (locked) when the reverse brake 30b is operated.

  The rotation of the counter shaft CS is transmitted to the secondary shaft SS via the reduction gears 34 and 36, and the rotation of the secondary shaft SS is transmitted to the left and right drive wheels (tires, only shown on the right side) W via the gear 40 and the differential D. It is done. A disc brake 42 is disposed in the vicinity of the drive wheel W.

  Switching between the forward clutch 30a and the reverse brake 30b is performed by the driver operating a shift lever 44 provided at a vehicle driver's seat, for example, having positions P, R, N, D, S, and L. When any position of the shift lever 44 is selected by the driver, the selection operation is transmitted to a manual valve of a hydraulic mechanism (described later) such as the CVT 26.

  For example, when the D, S, and L positions are selected, the spool of the manual valve moves accordingly, and hydraulic oil (hydraulic pressure) is discharged from the piston chamber of the reverse brake 30b, while hydraulic pressure is discharged to the piston chamber of the forward clutch 30a. Is supplied and the forward clutch 30a is engaged (fastened).

  When the forward clutch 30a is engaged, all gears rotate together with the main shaft MS, and the drive pulley 26a is driven in the same direction (forward direction) as the main shaft MS.

  On the other hand, when the R position is selected, hydraulic oil is discharged from the piston chamber of the forward clutch 30a, while hydraulic pressure is supplied to the piston chamber of the reverse brake 30b, and the reverse brake 30b is operated. As a result, the carrier 30c4 is fixed, the ring gear 30c2 is driven in the opposite direction to the sun gear 30c1, and the drive pulley 26a is driven in the opposite direction (reverse direction) to the main shaft MS.

  When the P or N position is selected, the hydraulic oil is discharged from both piston chambers, the forward clutch 30a and the reverse brake 30b are both released, and the power transmission through the forward / reverse switching device 30 is cut off. Power transmission between the engine 10 and the drive pulley 26a of the CVT 26 is interrupted.

  FIG. 2 is a hydraulic circuit diagram schematically showing a hydraulic mechanism such as the CVT 26 described above.

  As shown in the figure, a hydraulic pump 46a is provided in the hydraulic mechanism (indicated by reference numeral 46). The hydraulic pump 46a is a gear pump, is driven by the engine 10, pumps up hydraulic oil stored in a reservoir (hydraulic supply source) 46b, and pumps it to a PH control valve (PH REG VLV) 46c.

  On the other hand, the output (PH pressure (line pressure)) of the PH control valve 46c is supplied from the oil passage 46d via the first and second regulator valves (DR REG VLV, DN REG VLV) 46e, 46f. Are connected to the piston chamber (DR) 26a21 of the movable pulley half 26a2 and the piston chamber (DN) 26b21 of the movable pulley half 26b2 of the driven pulley 26b, and on the other hand, the CR valve (CR VLV) via the oil passage 46g. 46h.

  The CR valve 46h reduces the PH pressure to generate a CR pressure (control pressure), and the first, second and third (electromagnetic) linear solenoid valves 46j, 46k, 46l (LS-DR, LS) from the oil passage 46i. -DN, LS-CPC). The first and second linear solenoid valves 46j and 46k act on the first and second regulator valves 46e and 46f with the output pressure determined in accordance with the excitation of the solenoid, so that the PH pressure is actuated from the oil passage 46d. Oil is supplied to the piston chambers (oil chambers) 26a21 and 26b21 of the movable pulley halves 26a2 and 26b2, and a pulley side pressure is generated accordingly.

  Therefore, in the configuration shown in FIG. 1, the pulley side pressure that moves the movable pulley halves 26a2 and 26b2 in the axial direction is generated, the pulley widths of the drive pulley 26a and the driven pulley 26b change, and the winding radius of the belt 26c changes. Changes. Thus, by adjusting the side pressure of the pulley, the transmission gear ratio for transmitting the output of the engine 10 to the drive wheels W can be changed steplessly.

  Returning to the description of FIG. 2, the output (CR pressure) of the CR valve 46h is also connected to a CR shift valve (CR SFT VLV) 46n, and from there through the above-described manual valve (MAN VLV, indicated by reference numeral 46o). The forward clutch 30a of the forward / reverse switching device 30 is connected to a piston chamber (FWD) 30a1 and a piston chamber (RVS) 30b1 of the reverse brake 30b.

  As described with reference to FIG. 1, the manual valve 46o outputs the output of the CR shift valve 46n according to the position of the shift lever 44 operated (selected) by the driver 30a1 of the piston chamber of the forward clutch 30a and the reverse brake 30b. , 30b1.

  The output of the PH control valve 46c is sent to the TC regulator valve (TC REG VLV) 46q via the oil passage 46p, and the output of the TC regulator valve 46q is LC shifted via the LC control valve (LC CTL VLV) 46r. Connected to valve (LC SFT VLV) 46s. The output of the LC shift valve 46s is connected on the one hand to the piston chamber 24c1 of the lock-up clutch 24c of the torque converter 24, and on the other hand to the backside chamber 24c2.

  The CR shift valve 46n and the LC shift valve 46s are connected to first and second (electromagnetic) on / off solenoids (SOL-A, SOL-B) 46u and 46v, and the oil to the forward clutch 30a is excited or de-energized. The switching of the road and the engagement (on) / release (off) of the lock-up clutch 24c are controlled.

  Regarding the lock-up clutch 24c, the hydraulic oil is supplied to the piston chamber 24c1 via the LC shift valve 46s, while the lock-up clutch 24c is engaged (fastened and turned on) when discharged from the rear chamber 24c2. While being supplied to the chamber 24c2 on the back side, when discharged from the piston chamber 24c1, it is released (not fastened. OFF). The slip amount of the lock-up clutch 24c, that is, the engagement capacity when the lock-up clutch 24c is slipped between engagement and release is determined by the amount of hydraulic oil (hydraulic pressure) supplied to the piston chamber 24c1 and the rear chamber 24c2. The

  The third linear solenoid 46l described above is connected to the LC shift valve 46s via the oil passage 46w and the LC control valve 46r, and further connected to the CR shift valve 46n via the oil passage 46x. That is, the engagement capacity (slip amount) of the forward clutch 30a and the lockup clutch 24c is adjusted (controlled) by the excitation / non-excitation of the solenoid of the third linear solenoid valve 46l.

  Returning to the description of FIG. 1, a crank angle sensor 48 is provided at an appropriate position such as near the cam shaft (not shown) of the engine 10 and outputs a signal indicating the engine speed NE for each predetermined crank angle position of the piston. To do. In the intake system, an absolute pressure sensor 50 is provided at an appropriate position downstream of the throttle valve, and outputs a signal proportional to the intake pipe absolute pressure (engine load) PBA.

  The actuator of the DBW mechanism 16 is provided with a throttle opening sensor 52 and outputs a signal proportional to the throttle opening TH through the amount of rotation of the actuator, and an accelerator opening sensor 54 is provided in the vicinity of the accelerator pedal. A signal proportional to the accelerator opening AP corresponding to the accelerator pedal operation amount is output.

  Further, a water temperature sensor 56 is provided in the vicinity of a cooling water passage (not shown) of the engine 10 to generate an output corresponding to the engine cooling water temperature TW, in other words, the temperature of the engine 10, and the intake air temperature in the intake system. A sensor 58 is provided and generates an output corresponding to the intake air temperature (outside air temperature) taken into the engine 10.

  The output of the crank angle sensor 48 and the like described above is sent to the engine controller 60. The engine controller 60 includes a microcomputer, determines the target throttle opening based on the sensor outputs, controls the operation of the DBW mechanism 16, and determines the fuel injection amount to drive the injector 20.

  The main shaft MS is provided with an NT sensor (rotational speed sensor) 62, which determines the rotational speed of the turbine runner 24b, specifically the rotational speed of the main shaft MS, more specifically the input shaft rotational speed of the forward clutch 30a. The pulse signal shown is output.

  An NDN sensor (rotational speed sensor) 66 is provided at an appropriate position near the driven pulley 26b of the CVT 26 and outputs a pulse signal indicating the rotational speed of the driven pulley 26b.

  In this embodiment, the NDR sensor that is arranged in the vicinity of the drive pulley 26a of the CVT 26 and outputs a pulse signal according to the rotational speed of the drive pulley 26a, in other words, the output shaft rotational speed of the forward clutch 30a, is removed. It assumes a configuration (or a configuration that is arranged but not used for control).

  A VEL sensor (rotational speed sensor) 70 is provided in the vicinity of the gear 36 of the secondary shaft SS, and outputs a pulse signal indicating the output shaft of the CVT 26 or the vehicle speed VEL through the rotational speed of the gear 36. A shift lever position sensor 72 is provided in the vicinity of the shift lever 44 described above, and outputs a POS signal corresponding to a position such as R, N, or D selected by the driver.

  The output of the NT sensor 62 and the like described above is sent to the shift controller 74 including the outputs of other sensors (not shown). The shift controller 74 also includes a microcomputer and is configured to be able to communicate with the engine controller 60.

  Based on these detected values, the shift controller 74 selects one of the first and second on / off solenoids 46u and 46v of the hydraulic mechanism 46 and the first, second and third linear solenoid valves 46j, 46k and 46l. These electromagnetic solenoids are energized / de-energized to control the engagement (engaged, on) / release (non-engaged, off) of the lockup clutch 24a of the forward switching device 30, the CVT 26, and the torque converter 24.

  FIG. 3 is a flowchart showing the operation of the shift controller 74. The illustrated program is executed by the shift controller 74 at a predetermined time, for example, every 10 msec during in-gear.

  Explained below, in S10, it is determined whether or not the neutral (N) position is selected by the driver and the forward clutch 30a is released.

  When the result in S10 is affirmative, the program proceeds to S12, in which it is determined whether the accelerator is OFF, that is, whether the accelerator pedal is not operated by the driver, in other words, whether the throttle opening is fully closed. Then, the engine rotational speed NE is set as a target value, and the turbine rotational speed NT is set as a controlled variable to calculate a deviation between them. The engine speed NE and the like are detected via the engine controller 60.

  Next, in S16, a feedback gain for the neutral position is set (calculated) based on the calculated deviation. The feedback gain is set as the P term and I term of PI control.

  Next, in S18, the thrust of the drive pulley 26a and the driven pulley 26b is calculated.

  The thrust of the drive pulley 26a and the driven pulley 26b is calculated as a belt slip guarantee thrust based on the input torque determined from the engine speed NE and the engine load (absorption pipe absolute pressure PBA). For the driven pulley 26b, the transmission ratio holding thrust determined from the target transmission ratio (RATIO) is added to the belt slip guarantee thrust, and further based on the feedback gain set in S16 (the engine speed NE and the turbine speed). Calculate by adding the calculated thrust (so that NT is equal).

  Next, in S20, the calculated thrust is converted according to an appropriate conversion characteristic, and the hydraulic pressure to be supplied to the drive pulley 26a and the driven pulley 26b is calculated.

  FIG. 4 is a block diagram showing the processing of FIG.

  As described above, according to the present invention, when the forward clutch 30a is in the neutral position where the forward clutch 30a is released, the turbine rotational speed NT tends to be dragged to the engine rotational speed NE and the rotational speed of the drive pulley 26a by the hydraulic oil remaining in the forward clutch. It is premised on the knowledge that when the turbine rotational speed NT matches the engine rotational speed NE, the rotational speed NDR of the drive pulley also matches them.

  That is, the idling speed at the neutral position is constant, but feedback control is performed on the hydraulic pressure supplied to the drive pulley 26a and the driven pulley 26b so that the driving speed NDR matches the idling speed regardless of the vehicle speed. I tried to do it.

  In this way, by assuming that the drive pulley rotational speed is constant regardless of the vehicle speed, the trajectory when RATIO (transmission ratio, drive pulley rotational speed NDR / driven pulley rotational speed NDN) returns to the low side as the vehicle speed decreases is obtained. Therefore, the control accuracy of RATIO can be improved.

  On the other hand, when the result in S10 is negative, the program proceeds to S22, and since the forward clutch 30a is engaged, the output of the NT sensor 62 is regarded as the rotational speed NDR of the drive pulley 26a, and the drive pulley 26a set as appropriate is used. A deviation from the target NDR (target rotational speed) is calculated.

  Next, in S24, based on the calculated deviation, a feedback gain for travel (for position) such as D is similarly set as the P and I terms of PI control.

  Next, in S26, the thrust of the drive pulley 26a is calculated as a belt slip guarantee thrust, and the thrust of the driven pulley 26b is calculated based on the belt slip guarantee thrust, the transmission ratio holding thrust, and the feedback gain set in S24. Calculated as the addition value of

  On the other hand, when the result in S12 is negative, the program proceeds to S28, in which the thrust ratio between the drive pulley 26a and the driven pulley 26b is set to a fixed value.

  As described above, in this embodiment, the belt having the drive pulley 26a and the driven pulley 26b is connected to the engine (internal combustion engine) 10 mounted on the vehicle 14 via the torque converter 24 and the forward clutch 30a. In a control device (shift controller) 74 of the CVT (continuously variable transmission) 26 of the formula, a crank angle sensor (engine speed sensor) 48 for detecting the engine speed NE and a turbine speed NT of the torque converter 24 NT sensor (turbine rotational speed sensor) 62 for detecting the oil pressure, oil chambers of drive pulley 26 and driven pulley 26b, that is, piston chambers 26a21 and 26b21 of movable pulley halves 26a2 and 26b2, and a reservoir (hydraulic supply source) ) Between the oil passage 46d and the oil passage 46d. It is determined that the first and second (electromagnetic) linear solenoid valves (hydraulic pressure adjusting valves) 46j and 46k to be adjusted, the throttle opening is in the fully closed position, and the neutral position in which the forward clutch 30a is released. The hydraulic pressure supplied to the drive pulley 26a and the driven pulley 26b so that the turbine rotational speed NT coincides with the engine rotational speed NE, the first and second linear solenoid valves (hydraulic adjustment valves) 46j, Since it is configured to include feedback control means (S14 to S20) for feedback control via 46k, the control accuracy of RATIO (speed ratio) can be improved.

  In the above description, the NDR sensor arranged near the drive pulley 26a of the CVT 26 and outputting a pulse signal according to the rotational speed of the drive pulley 26a, in other words, the output shaft rotational speed of the forward clutch 30a has been removed. Is valid if the configuration does not use the control even if the NDR sensor is arranged.

  Moreover, although CVT26 was disclosed as an automatic transmission, it is not limited to it, This invention is applicable also to another automatic transmission.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an overall control device for a continuously variable transmission according to an embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram showing a hydraulic mechanism of a continuously variable transmission and a torque converter shown in FIG. 1. It is a flowchart which shows operation | movement of the apparatus shown in FIG. It is a control block diagram explaining the operation | movement shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Internal combustion engine (engine), 14 Vehicle, 16 DBW mechanism, 24 Torque converter, 26 Continuously variable transmission (CVT), 30 Forward / reverse switching device, 30a Forward clutch (clutch), 46 Hydraulic mechanism, 46j, 46k Hydraulic adjustment valve (First and second linear solenoid valves), 46s switching valve (LC shift valve), 56 water temperature sensor, 58 intake air temperature sensor, 60 engine controller, 74 shift controller

Claims (1)

In a control device for a belt-type continuously variable transmission connected to an internal combustion engine mounted on a vehicle via a torque converter and a clutch, and having a drive pulley and a driven pulley,
a. An engine speed sensor for detecting the speed of the internal combustion engine;
b. A turbine speed sensor for detecting the turbine speed of the torque converter;
c. A hydraulic pressure adjusting valve that is inserted in an oil passage between an oil chamber and a hydraulic pressure supply source of each of the drive pulley and the driven pulley, and adjusts a hydraulic pressure of the oil passage;
d. When it is determined that the throttle opening is in the fully closed position and in the neutral position where the clutch is released, the drive speed and the driven pulley are supplied so that the turbine speed matches the engine speed. Feedback control means for feedback-controlling the hydraulic pressure to be performed via the hydraulic pressure adjustment valve;
A control device for a continuously variable transmission.

Images